The Excavation of Two Bronze Age Burial Cairns at Bu Farm, Rapness
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Proc Soc Antic/ Scot, 126 (1996), 103-120 The excavation of two Bronze Age burial cairns at Bu Farm, Rapness, Westray, Orkney John Barber,* Alan Duffy* & Jerry O'Sullivanf with contribution Katy b s h McSweeny, Coralie Mill& s Tanya O'Sullivan ABSTRACT Excavation recorded largetwo cairns with dry stone third,a kerbs and miniature cairn similarof construction. Each of the large cairns contained a central, slab-built cist. Burnt deposits with bone inclusions underlay basalthe slabs bothof cists. third,The smaller cairn covered whichpit a also contained burnt deposits. crematedThe remains largertwo from the cairns appear representto a single adult in each case. Faunal remains from Cairn 1 include bones of a range of mammals, birds and fish. Radiocarbon dates indicate that the cairns were built in the mid- to late second millennium BC. Excavation and publication were funded by the former Historic Buildings & Monuments section of the Scottish Development Department (now Historic Scotland). INTRODUCTION CIRCUMSTANCE EXCAVATIOF SO N Excavations at Bu Farm, Rapness, were undertaken over a five-week period in May-June 1985 and formed part of a programme of investigation of sites threatened by coastal erosion. Other excavated sites in this programme included the chambered cairn at Point of Cott (Barber 1988; 1992; and forthcoming burna d tan ) moun t Gilda l Pier (Lehane 1990). This wor conductes k wa forme e th y db r Central Excavatio Historie s fundenth wa Uni y d b dc an t Building Monumentd san s sectioe th f no Scottish Development Department. THE CAIRNS Site description e excavateTh d cairn groua e par f ar s o f tthre po e large mounds (illu ) whic1 s h were previously recorde Orknee th y db y Islands Archaeologist r RaymonD , d Lamb. The describee yar d accordingly sitee i nth monument s& s Inventor islane th r f Westraydo yfo : Two mounds lie in the south-west corner of the pasture field north of Stancro House. The larger [Cairn 500Y H shoreline 1]6t th beina ,s 4044 i n o d gs i an e, eroded t comprisei ; survivine th s g circulahala f o f r (ScotlandC AO * ) Schoolhousee LtdTh , Lochen4 , d Road, EdinburgR 8B 6 hEH t 5 Bellevue Road, Edinburgh EH7 4DA 104 I SOCIETY OF ANTIQUARIES OF SCOTLAND, 1996 Shoreline Mounds ILLU S1 Site location plan Ordnance(Basede th n o CrownSurvey© p ma Copyright) BARBER, DUFFY & O'SULLIVAN: BRONZE AGE BURIAL CAIRNS AT BU FARM I 105 bank of about 14 m overall, 0.4 m high, at the south end of which, on the shoreline, two courses of an outer revetmen e visiblear t . Withihollowa s i t ni , the centrana l knoll containin glarga e cis r smalo t l slab-formed chamber, of which the north side is represented by an upright stone aligned east-west, 1.7 high m e knol 7 Th .s compose0. i l lon m d gan f largdo e slabs laid slantwise face-to-face; this sits i e probably a 'bell-cairn'. To the south [Cairn 2], at HY 5007 4042, is a grass-grown mound 9 m in diameter, 0.3 m high, its top hollowed. Further north, in the same field, at HY 4013 4049, is a grass-covered mound slabhighw m fe diamete n i s5 a ; 0. protrudm d 8 an r t severaa e l points aroun edge dth e (Lamb 1983, 25). time th excavationf et o A cairne th , s wer describeds ea foune b o dt , though excavation would demon- strate that, in this case, the 'bell-cairn' profile of Cairn 1 was due to disturbance rather than design. Erosion The cairns occupy an exposed site. Cairn 1 is located at the present shoreline and marine erosion had already claimed almost half of the monument at the time of excavation (illus 2). Cairn 2, at a distance of several metres from the shoreline, was subject to an additional threat. Here, a farm track traversed the narrow 4 m span between the two cairns. The passage of livestock and farm machinery was impinging on Cairn 2 and threatened to destroy any potential stratigraphic links between the cairns. EXCAVATION RESULTS CAIRN 1 Intrusion stone-robbingand s clearlCairwa n1 y disturbe numbea n di f wayso r layeA . f smalleo r r stony debris littere e surface dth th f o e cair formed nan uppee dth ciste rth .filf Thio l s interpretei s remnane th s da t debri f selectivso e stone-robbing. e resul On f stone-robbino t s tha e i cairge heighs irregularl th th t wa nf o t y reduced, resultin n annulaa n i g r depression around the cist (illus 3). It was this which produced the 'bell-cairn' profile which had previously been recorded (Lamb 1983, 25). cise tTh itsel thoroughls wa f y robbed recognizablo N . y primary deposits (skeletal remain gravr so e goods) were found basae withiTh . l nit slas broke bwa n throug burnd han t deposits underlyin t wergi e disturbed. The cairn body and kerb maie Th n bod f survivinyo g cairn material consiste f randomldo y dumped slabs (F457) clay-loaA . m soil matrix (F401) was concentrated towards the base of the cairn and may be an inwashed or secondary sediment. These materials forme semicirclda f kerb-revetteeo d rubble wit overaln ha maximua d lan diametem m 4 1 heigh f o r t of 0.5 m. The retaining kerb was a well-built drystone wall (F446). This consisted of medium-large flat stone slabs, raised to three or four courses, and surviving to an overall height of c 0.4 m. The stones were laid so that the outer edges formed a fair-faced curvilinear wall face, while the more ragged, inner edges were keyed into the rubble body of the cairn. Towards the centre of the cairn, the slabs were more deliberately placed. Here, quantitie largef so r slabs were erecte endn do , formin seriega concentricf so , interleaving circle f stonso e which inclined against a central cist (illus 4). 106 I SOCIETY OF ANTIQUARIES OF SCOTLAND, 1996 N F.456 Basal slabs Limit of excavation 5m ILLUS 2 Plan of the excavated area: the 'miniature cairn' lies immediately south of Cairn 1 jo 03 O Cfl z w 7> O N wO ILLU S3 Cairn 1: cross-section recorde erodine th t da g seawar monumende th fac f o e t CO n w JO 10 I 8SOCIET ANTIQUARIEF YO SCOTLANDF SO , 1996 ILLUS 4 Cairn 1: roughly concentric rows of interleaving flat stones incline against the cis The cist The cist (F456) consisted of two large slabs forming the north (1.9 m by 0.65 m) and south (0.9 m by 0.65 m) sides of a compartment 0.8 m wide. These side slabs were erected on edge upon a large, horizontal basal slab (1.75 m by 1.3 m). Other slabs may have once formed the east and west sides of the cist, and perhaps a cover, but these were not found in situ. Underlying deposits The basal slab did not rest directly upon the buried natural ground surface, but on a spread of dark soil (F406, F407) that included charcoal and burnt bone fragments. Some of this material (F407) may have been intruded from the cist at the point where the basal slab was broken through (illus 5), but it was also possible to identify undisturbed material (F406) whic clearld hha y been deposited befor constructioe eth ciste th .f nMateriao l from this context was submitted for radiocarbon dating and returned a determination of 2955 ± 85 BP (AA-11766); materiae th l from which this datderives ewa alsy odma have contained driftwood (see Mills, below). CAIRN 2 The cairn body and kerb secone Th d cair smallea s ni r monument, sited several metres fro presene mth t shorelinsouth-easm 4 d ean f o t overale CairTh . constructioe n1 l Th diametet survive i . monumend e m heighth a an 8 f o 0. f st ro m n o f 9 o t s i t BARBER, DUFF O'SULLIVANY& : BRONZ BURIAE EAG L9 CAIRN 10 FARU B I T MSA ILLU S5 Cairn broke 1the : n slab which underla cisythe t this monument was similar to that of Cairn 1, with dumps of stony rubble (F452) surrounding a central rosette of large slabs, erected on edge and inclined against a central cist. The kerb consisted, again, of a well-built drystone wall (F447), brough even a no t t oute e finisthren th i t r ra hm e o face raised 4 heigha 0. an , o c dt f o t four courses of large, flat slabs (illus 6). The cist contrasn I Cairo t t n centra e 1th , l cist (F433 intacs Cairn i )appeared wa an nt 2 undisturbede b o dt largeo Tw . , rectangular slabs forme ease wesd dth an t t ciste sideth .f so Smalle r slabs were fitted between the formo t e mth north and south sides. The cover-slab was close-fitting and appeared to be in its original position. The side-slabs were erected upon a flat, rounded basal slab (diam 1.4 m) and were retained by a loose clay-loam soil (F435) heaped against their outer faces. Overall, the cist formed by this setting of stones was small and very regular, approximating to a cube, with sides and base all measuring c 0.3 m.